Study On Static Torque Characteristics Of 3-DOF PM Spherical Motor

Three degree of freedom(3-DOF)permanent magnet spherical motor is a kind of electromechanical energy conversion device with spherical structure,novel operation mechanism,high integration and multi-dimensional movement,which has a very wide application prospect.However,it is still in the theoretical exploration and experimental stage,and many problems such as static torque characteristics and current solution need to be solved urgently.The specific research contents of this paper are as follows:Firstly,the structure and working principle of the permanent magnet spherical motor are given.According to the electromagnetic force and static torque characteristics of the stator at different coordinate positions,the three-dimensional finite element simulation model of static torque of permanent magnet spherical motor is established by current vector magnetic position method.The electromagnetic force and static torque distribution of individual stator windings at various positions on the spherical surface of the rotor are analyzed.The influence of stator structure parameters on torque is studied.Applying a linear current to a single stator coil results in a relationship between static torque and current.Secondly,in order to obtain the ideal torque model,the MATLAB polynomial fitting algorithm and the segmentation fitting method are used to fit the static torque data of the single stator coil obtained by simulation.And the continuous static torque polynomial formula of a single stator coil with current value of 1A is obtained.The mutual conversion algorithm between the spherical coordinate system of the rotor motion and the fixed spherical coordinate system of the stator are established by the Euler angle transformation matrix.Based on the fitted continuous static torque polynomial formula of single stator coil,the torque model and current solving algorithm for multiple stator coils are established.Finally,based on the subject,there are permanent magnet spherical motor prototypes and equipments.The metal sheet pressure sensor system is used as the main measuring equipment,and the experimental platform of the permanent magnet spherical motor system is built.The experimental data of the electromagnetic force _zF on the rotor in the direction of x-axis are collected,and the simulation data are verified.Experiments show that the permanent magnet spherical motor simulation model established by the three-dimensional finite element analysis software in this paper can accurately and effectively simulate the electromagnetic force and static torque characteristics of the permanent magnet spherical motor.